The ongoing miniaturization of hand-held multi-media devices such as Personal Digital Assistants (PDAs) or mobile phones in recent years appears to be only bounded by the perceptual limits of the human user. This particularly applies to the design of the displays of hand-held devices, with a remarkable trend to increase the relative area of the hand-held device that is consumed by its display. However, the display sizes of hand-held devices are necessarily significantly smaller than the display sizes for which content is usually designed. If for instance content of the World Wide Web (WWW), i.e. web pages formatted according to the Hypertext Markup Language (HTML) or derivatives thereof (such as Extensible HTML (XHTML)), is to be displayed on the hand-held device, it has to be considered that these web pages are normally designed for portrayal on a computer monitor, the dimensions of which are by a factor 8-10 larger than the display dimensions of a hand-held device such as a mobile phone.
Viewing web pages on the display of a hand-held device requires horizontal and vertical scrolling with scroll bars, which is generally experienced as uncomfortable or even annoying for the user of the hand-held device. Consequently, most browsers that are installed in hand-held devices and provide for the interpretation of the web page content offer the possibility to view web pages in a format that is optimized for the display dimensions of the hand-held device.
The well-known technique for this optimization is to scale the web page so that it fits to the width of the display of the hand-held device. This scaling technique for web pages in order to avoid horizontal scrolling is for instance disclosed in US patent publication US 2002/0021308 A1.
HTML and XHTML standards specify a so-called image map object, that is used to define selectable areas inside an image. Such an image map is exemplarily depicted in FIG. 1. The image map is basically an image 1 that is composed of several image regions 1-1 . . . 1-6, where at least some of said image regions 1-1 . . . 1-6 basically work as image hyperlinks. An image hyperlink is an HTML object defining an image that is selectable by the user and is associated with a web resource, the Uniform Resource Locator (URL) of which being defined in the anchor hyperreference field of the image hyperlink. When the image is selected, the browser fetches the web resource that is defined in the anchor hyperreference, which may be a web page, a sound, video, etc. Quite similar, textual hyperlinks are HTML tags with selectable text instead of selectable images, and voice hyperlinks are HTML tags with speech input options instead of selectable images.
Within an image map 1, it is also possible to include image regions that are not associated with a web resource and serve as inactive image region only. When the user selects an image region 1-1 . . . 1-6, either by moving a mouse pointer on the image region 1-1 . . . 1-6 and clicking, or by using a touchscreen, keyboard input or a voice command, the browser downloads the web resource that is associated with that image region 1-1 . . . 1-6. That web resource may contain further images, texts, sounds, videos or scripts that then are executed by the browser.
Image maps are widely used on web pages, in particular as web page menus, but also to simplify navigation in huge text documents, e.g. Portable Document Format (PDF) documents and Word documents, or in road maps. In most cases, they are wider/higher than the display width/height of the hand-held device. Consequently, when scaling web pages down to fit to the width/height of the hand-held display, image maps are scaled down as well.
FIG. 2 depicts the result achieved when scaling is applied to the image map of FIG. 1, which was designed for portrayal on a computer monitor. Apparently, the image regions of the scaled image map, now optimized for portrayal on the display of a hand-held device, are no longer identifiable, and navigation based on the scaled image map is no longer possible.
One way to navigate with such a scaled image map is to rely on the definition of so-called alternative texts for each image region. Alternative texts are optional in the definition of image hyperlinks and image hyperlinks within image maps, and specify a text that appears when the mouse pointer is pointed to an image or image region. In the example of FIG. 2, when moving the mouse pointer to image region 1-4, the browser displays the text “Mail”, if the alternative text of this image region 1-4 was defined as “Mail”, or displays no text, if the alternative text of this image region 1-4 was not defined.
A further solution to the problem of image maps that have been scaled down beyond recognition is to display the scaled image map in a way that the image hyperlinks within the scaled image map 2 corresponding to image map regions 2-1 . . . 2-6 are deactivated. Instead, the browser extracts the hyperreferences corresponding to each image region 2-1 . . . 2-6 and uses said hyperreferences as hyperreferences of textual hyperlinks, that are displayed next to the scaled image map. However, the text representing the textual hyperlinks can only be based on the alternative texts defined for each image region 2-1 . . . 2-6 within the image hyperlinks, or on the hyperreferences themselves, which are usually Uniform Resource Locators (URLs), which are in general long character strings that do not allow conclusions on the type of target object they refer to.
Finally, some browsers support switching between the display of the scaled web page and the original size web page. When displaying the original size (unscaled) web page, usually horizontal and vertical scroll-bars are required for visual inspection of the web page. Thus it is possible for the user to switch to the original size web page when the scaled web page does no longer allow for navigation due to scaled site maps whose image regions can no longer be identified. However, switching between scaled and unscaled web pages requires advanced operating skills of the user, and represents a rather complicated approach.